What do you think Amir;s dream means?

Didn't you mean Hassan's dream? Hassan’s dream is significant because although it appears absurd and fantasy-like in Amir’s mind, the dream is a symbol of the strengths and weaknesses in Amir and Hassan’s relationship. The part of the dream where Amir courageously dives into the lake and Hassan follows represents their bravery, companionship, and ability to work together during the kite fighting tournament. Amir relies on Hassan more than Hassan will ever know, and Hassan has built a sense of trust in Amir since birth. The part of the dream where the alleged monster doesn’t exist however is ironic, because although Hassan’s humble nature leads him to believe that even cruel humans should be forgiven, the truth is that in humanity, monsters do exist, and Amir is one of them. Amir has a selfish, cowardice side, which is clearly revealed in this chapter.